Mechanism for varying the tension of normalizing springs of typewriters or like machines



P 18, 1951 w. H. KUPPER 2,567,946

- MECHANISM FOR VARYING THE TENSION OF NORMALIZING SPRINGS OF TYPEWRITERS OR LIKE MACHINES 2 Sheets-Sheet 1 Filed Jan. 9} 1950 Jim W lma.

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MECHANISM FOR VARYING THE TENSION 0F NORMALIZINGk SPRINGS OF TYPEWRITERS 0R LIKE MACHINES 2 Sheets-Sheet 2 Filed Jan. 9, 1950 g u 6% m G s Q I W -1 V W- V I I I I I I I I I l I I ll I V: v M i T .1. 0 I WW6 m /A g. w m M r////Y/// bh I Q$QM |NI n n v mm T \Q v I u f u m "m -||I.||-|-l.-|||||.. 4 7 n. I V: n c I v .I 4 h .29 I I w m Ila. ahnh r l hn f.|| a j 7 mN NN Wk Patented Sept. 18, 1951 MECHANISM FOR VARYING Tnm'ENsmN F NORMALIZING SPRINGS OF TYPE;- WRITERS on LIKE MACHINES William H. Kuppcr, West Hartford, Conn., as- 1 signor to Royal Typewriter C'ompany, Inc., New York, N. Y., a corporation of New York Application January 9, 1950 Serial No. 137,558

14 Claims. (01. 197 'ss) This invention relates to mechanism for varying the tension of normalizing springs of typewriter or like machines, and more particularly to mechanism for varying the tension of springs, the normalizing force of which has to be overcome by finger pressure applied to the space bar or keys of such machines, including power operated typewriters.

qThe prior art is replete with devices for adjusting the tension of springs which function to return key levers of typewriter or like machines to normal or non-depressed positions. The principal broad object of the present invention is to provide key or the like normalizing spring adjusting mechanism which is of novel and improved construction.

In some power operated typewriter constructions, a key is depressed to move an intermediate drive-transmitting,element into engagement with a continuously operating driving member, whereupon-the drive transmitting element is actuated soas in turn, to actuate an associated typewriter instrumentality, e. g., a type bar, carriage feeding .or back spacing mechanism, or any of the other well known typewriter mechanisms. In some such machines, each key lever is provided with a normalizing or returning spring, and the associated intermediate or drive-transmitting mechanism isprovided with one or more additional normalizing springs .for the appropriate parts. The arrangement is such that all of the normalizing springs associated with a particular mechanism group, for example, a typing key, type bar, actuating mechanism, and intervening connections, resist depression of the key. In the copending application of John F. Kloski, Serial No. 110,534, filed August 16, 1949, there is disclosed and claimed a power operated typewriter or the like normalizing spring arrangement in which the total normalizing force of a plurality of springs tending to resist depression of a single key is made accurately adjustable by providing mechanism for variably tensioning one or more but less than all of the springs associated with each key lever or other manually operable part. Mechanism constructed in accordance with the present invention may embody, and is disclosed herein as embodying this feature.

Another object of the present invention is to provide a normalizing spring adjusting mechanism which is simple in construction, efficient and reliable in operation, and is so constructed as to 'be easily mountable on and detachable from the machine frame or a part carried by the frame, and so" as to be readily accessible for servicing or adjustment when mounted.

Otherobjects of the invention will becomeapparent. from a reading of the following description, the appended claims, and the accompanylng drawings, in which: Figure 1 isa view, partly in elevation and partly in vertical section, foreand aft of a typewriter embodying the invention, showing only some of the conventional or standard typewriter parts inorder to illustrate the application of mechanism embodying the invention to a typewriter construction;

FigureZ is a fragmentary, vertical cross section showing some of the parts illustrated in Figure 1 on an enlarged scale and in different positions of adjustment; l

Figure 3 is a fragmentary, front elevation with a part of a front mask panel broken away so as to show parts of mechanism embodying the invention asviewed when looking in the direction of the arrow 3 in Figure 1;

Figure 4 is'a fragmentary horizontal section on the-line 4 4 o f Figure 3, drawn on an en larged scale;

Figure 5 is a detail, partly in section and partly in elevation, showing a portion of an anchor plate and stud for mounting the plate on the typewriter'frame; and

Figure 6 is a fragmentary vertical sectional view drawn on an enlarged scale and showing a modification.

The ventionmay be embodied in typewriters or like machines of various kinds. For the purposes of illustration, the invention is shown as being embodied in an ofiice type typewriter having, except for the power mechanism and spring tension adjusting mechanism to be described, inanyfeatures in common with the well known B oyal- Standardtypewriter. The drawings show only enough of the standard or known typewriter construction to assistin illustrating the manner in which mechanism embodying the invention may-be coordinated with otherparts of a typewriter constructiom v Theknown construction illustrated includes a main frameAon which a carriage B equipped with a pla'ten C is mounted for letter spacing and returnmovements by means of a top rail I secured .toithecarriage, and rolling upon balls 2, which'in turn are adapted to roll on a framemounted bottom rail or track 3. I

Th carriage may be driven toward the left,

' that is, in the letter-spacing direction, by any able escapement mechanism operated, for ex- 3 ample, as disclosed in the copending application of Henry J. Hart, Serial No. 98,738, filed June 13, 1949, now Patent No. 2,563,722 dated August 7, 1951.

Returning of the carriage toward the right may be effected-by power controlled from the typewriter keyboard, for example, by mechanism of the kind disclosed in the copending application of Henry J. Hart, Serial No. 21,476, filed April 16, 1948.

The machine is provided with the usual complement of type bars, one of which is shown at 4 in Figure 1 as being pivoted at 5 on a support or segment 6 equipped with a type bar abutment or banking ring 1. Normally the type bar 4 is in the position shown in Figure 1 with the type head resting upon a cushion 8. The type bar segment 6 may be shifted to upper and lower case positions by any suitable mechanism, for example, by power-operated mechanism of the kind shown in the copending application of William H. Kupper, Serial No. 133,322, filed December 16, 1949.

Power for operating the type bars or other instrumentalities is supplied by an electric motor (not shown), which drives an actuatin mechanism generally designated D. The mechanism D is generally similar to mechanism described and claimed in copendingapplication 98,738 referred to above, and is similar to but embodies improvements in mechanism disclosed in the copending application of William H. Kupper, Serial No. 6,066, filed February 3, 1948. It includes a continuously operating driving member and controllable-driving connections, which normally are inoperative or ineffective, but which may be conditioned by the operator to effect operative driving connection between the continuously moving driving member and the instrumentalities to be operated. The driver is constituted by a continuously rotating element, more particularly a toothed snatch roll or bar 9, which may be of known form, and which is adapted to be-driven in the direction of the arrow a in Figure 1.

The mechanism for transmitting drive from the driver '9' to each of the type bars 4 includes an actuator H] which extend fore-and-aft of the typewriter and above the member 9. The actuator I is pivoted as at H to a lever ['2 at a point oifset relatively to the pivotal mounting l3 of the lever on a fixed frame cross bar M. The actuator has a forwardly extending part l projecting under an abutment or guide plate [6 mounted by screws; I! on the frame A to extend parallel to the snatchroll 9. The downwardly extending part I5 of the actuator H] projects through a slot (not shown) in a lower guide plate l8 which is secured to the frame by the screws [7. The actuator part is cooperable with an adjustable knock-off plate or member I9 for a purpose to be described hereinafter. A normalizin spring is interposed between the front end of the actuator l0 and an anchor plate 2| secured by screws 22 (see Figures 3 and 4) to a fixed cross bar 23. The spring 20 normally maintains the actuator H1 in the position shown in Figure 1 with the front end It: of the actuator immediately below the upper guide plate It.

The guide plates 16 and I8 and the spring anchor 21 extend across the front of the machine, the guide plates being cooperable with other actuators and associated parts similar to anchor 2! serving to anchor springs connected to the other actuators and corresponding to the spring 20 shown in Figures 1 and 2.

A link 24, pivotally connected to the lever l2 and the heel of the type bar 4 at 25 and 26 respectively, causes the type bar to be-driven clockwise to printing position when the lever I2 is rocked counterclockwise in the manner described below.

In order to apply a power impulse to the type bar 4, the actuator H1 is operatively but indirectly connected to the driving member 9, the actuator itself never engaging the driving member. Mechanism for bringing about the operative connection of the actuator element ID to the member 9 includes an interponent pawl 21, pivoted as at 28 on the actuator. A spring 29, anchored to the actuator I0 and connected to the pawl 27, biases or urges the latter to rock clockwise so as to move its nose 2! into engagement with the snatch roll 9. maintained out of engagement with the snatch roll by the restraining action of a control 'ele' ment or trigger 30 which is pivoted as at 31 on the actuator l9.

face 33 on the pawl so as to prevent the spring 29 from rockin the pawl element 21 into transient drive-transmitting engagement or connection with the driving member 9. The pawl -21 is formed with an inclined resetter cam face 34 which is located just below the holding surface 33, and which is acted upon by the'tr'igger for rocking the pawl counterclockwise, and thus rethe actuator ill and its "associated part, and the setting it in normal, inoperative position.

Operator controlled means including a. manually operable key 35 pivoted at 36 on the frame A is provided for bringing about operative driv ing connection between the driver 9 and the ac tuator It. The key 35 has an upward projection 3'! disposed behind an arm 38 of an operat-- ing lever 39, pivoted as at 40 on the rramemounted cross bar 23. The lever 39 has anotherarm 4| on which a limber dog or flipper 42' ispivoted at 49. A spring 44 urges the limber-dog 42 to rock clockwise to yieldably retain it normal position of rest against a limit stop 4i and above an car 46 on the actuator l0. do 42 can swing counterclockwise from the tion shown in Figure 1, but cannot move clock wise from this position.-

A normalizing spring 47 is connected at its upper end to a third arm 48 on the intermediate lever element 39, and is connected at its lower end to the associated key member 35 The spring 41, which may have a fixed or non-ad just'able preloading under tension, tends to-h'old' the arm 3-8 of the lever 39 in contact with the extension 31 of the key lever 35; and vice verse.

A further normalizing spring, the p'reloading, of which may be adjusted by'structu're embody ing the invention, is associated with each of the mechanisms controlled by the respective key lo-=- vers 35. In the form shown, a straight clan: gated anchor pate 49 is mounted in front of the cross bar 23 to extend adjacent, parallel, and in spaced relation to the set of aligned inter: mediate levers 39, and is formed with a plurality of downwardly extending prongs 50, each bf which is disposed directly above an associated intermediate lever 39. Each prong 50 extends" into and thus positions the upper end'of a normalizing spring 5! interposed under compres sion between the anchor "plate 49 and the ai'ni' 48 of the associated intermediate lever 39; the

Normally, the pawl :is'

In the normal position of the' trigger, its rear end 32 engages a holding sur-' The ate-mac arms 43 being formed with-upwardly ex-tending tially under compression adjustable in amanner to be described later, they tend to rock the intermediate levers 39 counterclockwise so that,

in turn they urge the key levers 35 clockwiseto their normal or non-depressed inactive positions. 7 we The anchor 49 extends transversely of the-machine-so as to provide an anchorage for other springscorresponding to the spring| and connected to other intermediate levers such as the lever 39 shown in Figure 1. The springs 41 and 5| normally hold the key levers 35 and the intermediate levers 39 in the positions shown in Figure 1," so that thekey levers are in inactive position and the lower ends of the flippers 42 are positioned just above the ears 46 on the actuators |0.-

- In operation, when the key 35 is depressed,

the lever 39 is rocked clockwise to cause the flipper 42 to push the actuator downwardly toan initial extent sufficient to bring the trigger 30 into engagement with the abutment l8. This causes the trigger to be rocked clockwise about its pivot 3|, so asto release the pawl 21, which isthen moved by the spring 29 into engagement with the snatch roll 9.- The snatch roll then drives the pawl 21 and actuator H] as a unit so as to rock the lever l2 and operate the link 24 and type bar 4. When the pawl 21 is cast off from engagement with the snatch roll 9, the spring 29 lifts the actuator l6 to bring the trigger 30 into engagement with the upper, triggerresetting abutment 6. This causes the trigger 3|! to be rocked counterclockwise, so as to move its end 32 against the'resetting cam face 34 ofthe pawl 21, thereby'restoring the latter to its inactive position. The parts will then be returned to their normal positions by the coaction of the springs 26, 41, and 5|, and a spring 12 interposed between the rear of the frame A- and a link |2 connectedto the lever I2. 1

Means of the kind disclosed in the copending application of Henry J. Hart, Serial No 102,634, filed July 1, .1949, are provided for adjustingor varying the amount of driving impulse delivered to the individual pawl 21 by the snatch roll 9. The individual variation or adjustment is ef-' fected by variably limiting the extent to which the actuator pawl nose 21 enters a tooth inter space on'the snatch roll 9 under the urge of the spring '29 when the restraint of the trigger 39 on the pawl 21 is discontinued. In the form shown, the actuator |9 is provided with a downwardly extending stop element or linger 55 which is disposed in front of and normally out of contact with a downwardly extending stop part, heel, or finger 56 on the pawl 21. When the pawl 2! is rocked clockwise by the spring 29 so as to move the pawl nose 21*" into a snatch roll tooth interspace, the pawl stop 56 moves toward the actuator stop 55, which maybe so positioned as to be engaged by the stop 56 to arrest rocking of the pawl 21 before the tooth 2! moves to the root of the snatch roll tooth interspace. By variably positioning one of the stops 55, 56, e. g., by bending the stop 55 towards or away from the stop 56, the extent to which the pawl tooth 2| enters the tooth interspace can be varied. Consequently, the angle through which the snatch roll rotates while in contact with the pawl, which -determines the amount of driving ofthe pawl '21 and actuator III by the snatch roll 9, can be varied. Any suitable means or construction may be provided for adjusting one of the stops 55, 56 relatively to the other. In the preferred construction the stop 55 is formed integrally with the actuator l9 so as to be bendable toward or away from the stop 56.

A further variation of the impulse delivered to the actuators l0 may be effected by bending individual leaves or ears l9 of the knock-oi! bar I9 upwardly or downwardly to be engaged sooner or later by the lower end portions l5 of the actuators.

In accordance with the present invention, new and improved means is provided for mounting the anchor plate 49, and for adjusting it to vary the preloading of the compression springs 5| so as to adjust the touch or resistance to depression of the key levers 35. The springs 5|, being under compression, bias the intermediate lever elements 39 counterclockwise, and react upon the anchor plate 49, tending to raise it. Mechanism constructed in accordance with the invention comprises a simple and accessible arrangement for mounting. the anchor plate substantially at the junction of the rear or mechanism-mounting part of the frame A and the front or keyboard-enclosing part of the frame. In the form shown, the anchor plate 49 is formed so as to have a straight, fiat body part 49 and a ledge part 49 extending outwardly from the plane of the part 49 toward the front of the machine. The body part 49 is formed with two spaced slots 53 the longer dimensions of which extend transversely with respect to the plate 49, that is, vertically. The slots 53 receive guide studs 54--54 having threaded connection with the frame cross bar 23, the arrangement being such that the anchor plate 49 can move vertically as limited by the length of the slots 53, but is restrained against horizontal or longitudinal movement. The vertical movement of the plate 49, effected by mechanism to be described later, produces the desired effect of adjusting the preloading of the normalizing springs 5|.

Mechanism for adjusting the plate 49 include two levers '55 and 56 which are mounted respectively to rock on the guide studs 54. The studs 54 are formed with heads 54 '-5 which contact the front faces of the levers 55 and 56 for holding the latter in face-to-face contact with the body part 49* of the anchor plate 49 so as, in turn, to hold the anchor plate against the front face of the frame cross bar 23. The levers 55 and 56 are formed, respectively, with offset lower arms 55 and 56* which are positioned to bear against the ledge part 49 of the anchor plate 49, and thus to act in opposition to the normalizing springs 5|. Rocking of the levers 55 and 56 clockwise, as viewed in Figure 3, will cause the lever arms 55 and 56 to press downwardly against the anchor plate ledge 49, thereby forc-' ing the anchor plate downwardly and increasing the loading of the normalizing springs 5|. Conversely, rocking of the levers 55 and '56 counter clockwise, as viewed in Figure 3, enables the anchor plate to be moved upwardly by the springs 5|, allowing the latter to expand so as to decrease their preloading. The levers 55 and 56 are connected by link means generally designated 51 so as to rock in unison. Y A manually operable adjusting device for rocking the levers is carried by a bracket '58 mountedon'top of the spring anchor 2|, and is secured in place by two of the screws 22, as shown enemas in Figures? and 4. A shaft :59 journaled in the bracket .58 .carriesa rotatable adjusting member, as shown, a worm wheel 60 having a hub 51 secured to the shaft by means of a set screw 52. The .bracket 58 is formed with an upper horizontal ledge 63 which, together with the bottom of the bracket, journals a vertical spindle 6'4 equipped with a worm 65 meshing with the worm wheel -60. The spindle 64 is also fitted with a finger knob 66 by which the worm 65 can be turned so as to rotate the worm wheel 60.

The worm wheel as is operatively connected to the link means 51, so that, when the finger knob 65 is turned with consequent turning of the worm wheel 60, the link means will be shifted so as to rock thelevers 5'5 and :56. In the form shown. the link means '5? comprises two separate links 6] and 58 connected; respectively, between the lever 55 and the worm wheel 50, and between the lever 56 and the worm wheel 60. The link 61 is pivoted as at 69 to the lever 55,, and as at .lll to the worm wheel, while the link 68 is pivoted at 10 to the worm wheel and at H to the lever 66.

It will be apparent that, when the worm wheel 60 is turned in either direction from the position shown in Figure 3, the link means constituted by the links 61 and 68 will rock the levers 5'5 and 56 so as to effect raising or lowering of the anchor plate 49, and consequent adjustment of the preloading of the normalizing springs 5|. In

order that the adjustment of the normalizing.

springs may be indicated visually, the lever 55 is formed with an extension or pointer 12 which projects upwardly through a slot 13 in a ledge 14 at the'top of a front masking panel 15 secured to the frame A by screws one of which is shown .at 16 in Figure 1. A suitable scale or indicator part may be marked on the mask adjacent the slot 13, or, more simply, the left end of the slot 73 maybe marked with a minus sign indicating the position of the pointer 72 corresponding to the least preloading of the normalizing springs 5|, and the right end of the slot may be marked with a plus sign indicating the position of the pointer .corresponding to the maximum preloading of the normalizing springs. Such an arrangement is shown in Figure 3.

- Inasmuch as adjustments of the preloading .of the normalizing springs ordinarily will be infrequen't, it is preferred that the adjustingzknob .56 and ,pointer T2 be mounted so as to be covered by the usual machine hood Tl which is shown in Figure 1 as being hinged at 78 .to the rear part of the frame A.

The mounting of the anchor plate 49, levers 55 and 56, and link means 61 .on the cross bar 23 in front of the mechanism carried by the frame A makes the touch control or adjusting mechanism particularly accessible for servicing. .Any normalizing spring 5| may .be removed and replaced easily by merely first removing the front mask panel 15 without its being necessary to disturb any of the other mechanism. Moreover, the entire normalizing spring and adjusting mechanism may easily be removed by unscrewing the two guide studs 54, disconnecting the levers 55 and 55 .from the link means 51, or, alternatively, disconnecting the .link means 51 from the worm wheel 60, and then moving the disconnected parts forwardly as a unit or subassembly to separate them from the frame cross bar 23.

An operating advantage of the construction described is that, when the anchor plate is moved lneither direction from a position correspond ing "to the normal or average touch desired by or'recommended for .most operators, the variation nf the normalizing spring preloading at first takes place relatively rapidly, and then more slowly, thus reducing the chance of an operators inadvertently adjusting the spring loading more than is proper to either extreme condition. As shown in Figure 3, the adjusting member 60 the levers 55 and 55, and the link means 51 occupy normal or mid positions corresponding;

to van average desired spring loading, and are movable in opposite senses from these positions for increasing or decreasing the spring loading. The adjusting member-50, levers 55 and 56, and link means :51 .are so relatively proportioned and positioned or mounted with respect to each other that, when they are in their normal positions as shown in Figure 3, a line extending from .the axis of rotation of the adjusting member -60 to its point of connection at 10 to the link means 51 is perpendicular to the link means, and parallel to lines extending from the pivotal axes of the levers 55 and 56 to the points .of connection 69 and H of thelevers to thelink means. Consequently, successive equal increments of movement of the rotatable adjusting member 60 in either sense from its average position shown in Figure 3 will effect progressively diminishing increments .of movement of the levers 55 and 56, and, progressively, more gradual movement of the anchor plate :49, and, progressively, more gradual spring load variation.

The modified construction shown in Figure -6 is similar to :the construction described with reference to Figures 1 to -'5, inclusive, differing from it only in that the Figure 6 construction does not include spring corresponding to the supplemental normalizing springs 41 shown in Figure 1. In the Figure --6 "construction, the norna-lizirig springs 51 interposed between the anchor plate 49 and the arms 48 of the intermediate levers 39 :serve alone to hold the intermediate :levers in such positions as to maintain the flippers 42 out of contact with the :ears 4.6 on the actuators 110,-a-nd to maintain the associated key :levers 35 in their normal or non-depressed positions.

Preferred embodiments of touch control mechanism constructed in "accordance with the invention :have been described as applied to the typing :keys of a typewriter. Mechanism embodying the invention, :however, may be and is intended to be used in connection with the other keys of typewriter :or like machines, such as the space bar 19 indicated in Figure 1. It may also be applied connection with such other auxiliany -.or service keys as the shift key, hack spacing key, shift lock key, tabular key, margin release key, and the .carriage return key of a power operated typewriter.

The construction shown and described embody the invention in preferred forms, but it is intended :that the disclosure be illustrative rather than definitive, the invention being defined in the ap pended claims.

-I claim:

1. In a typewriter or like machine, a frame; instrumentalities to be operated; means for operating said instrumentalities including a pl-ue rality of mechanisms each comprising a fingeroper-able key member; "a spring anchor plate; means mounting .said plate on said frame for shifting movement towards and away from ele ments of said mechanisms; a plurality of pre loaded normalizing springs anchored .to said am 9 chor plate and being connected respectively to said mechanism elements for urging said key members to normal, inactive positions; two levers mounted in mutually spaced relation on said frame and having portions operatively connected to said anchor plate; a worm wheel; a manually operable worm for turning said worm wheel; and link means connecting said worm wheel to said levers for rocking said levers in unison to shift said anchor plate on said frame:

to thereby vary the loading of said springs.

2. In a typewriter or like machine, a frame; instrumentalities to be operated; means for operating said instrumentalities including a plurality of mechanisms each comprising a fingeroperable key member; a spring anchor plate;

means mounting said plate on said frame for shifting movement towards and away from elements of said mechanisms; a plurality of preloaded normalizing sprin s anchored to said ansprings. s

3. In a typewriter or like machine, a frame; instrumentalities to be operated; means for operating said instrumentalities including a plurality of mechanisms each comprising a fingeroperable key member; an elongated straight spring anchor plate; means mounting said plate on said frame to extend longitudinally along and.

in spaced relation to a set of corresponding elements of said mechanisms arranged substantially in a straight line and to be shiftable towards and from said elements; a plurality of pre-loaded normalizing springs anchored to said anchor plate and being connected respectively to said mechanism elements for urging said key members to normal, inactive positions; two levers mounted in mutually spaced relation on said frame and having portions operatively connected adjusting member to said levers for rocking the latter in unison to shift said anchor plate on said frame to thereby vary the loading of said, springs, said adjusting member, said levers, and said link means being adapted to occupy normal positions corresponding to an average desired spring loading and being movable in opposite senses from said normal positions for increasing or decreasing said spring loading, said adjusting member, said levers, and said link means being so relatively proportioned and positioned that when they are in said normal positions a line extending from the axis of rotation of said adjusting member to the point of connection of said adjusting member to said link means is perpendicular to said link means and is parallel to lines extending respectively from the axes of rocking of said levers to the points of connection of said levers to said link means, whereby successive equal increments Of movement of said adjusting member in either sense from its normal positionwill eifect progressively diminishing increments of movement of said levers and progressively. more gradual movement of said anchor plate and spring load variation. c

5. In a typewriter or like machine, a frame; instrumentalities to be operated; means for operating said instrumentalities includinga plurality of mechanisms each comprisinga finger-operable key member; a spring anchor plate; means mounting said plate on said frame for shifting movement towards and away from elements of said mechanisms; a plurality of pre-loaded normalizing springs anchored to-said anchor plate and being connected, respectively to said mechanism elements forturging said key members to normal, inactive positions; twolevers mounted in mutually spaced relation to rock about parallel axes on said frame and having portions operatively connected to said anchor plate; a worm wheel; a manually operable worm for, turning said worm wheel; and link means connectingsaid worm wheel to said levers for rocking saidlevers in unison to shift said anchor plate on said frame to thereby vary the loadingrof said springs, said worm wheel, said levers, and said link means being adapted to occupy normal positions corresponding to an average desired spring loading to said anchor plate; a worm wheel; a manually operable worm for turning said worm wheel; and link means connecting said worm wheel to said levers for rocking said levers in unison to shift said plate selectively toward or away from said mechanism elements to thereby vary the loadabout parallel axes on said frame and having portions operatively connected to said anchor plate; an adjusting member mounted on said frame to turn about an axis parallel to the axes of said levers; and link means connecting said and being movable in opposite senses from said normal positions for increasing or decreasing said spring loading, said worm wheel, said levers, and said link means being so relatively proportioned and positioned that when they are in said normal positions a line extending from the axis of rotation of said worm wheel tothe point of connection of said worm wheel to said link means is perpendicular to said link means and is parallel to lines extending respectively from the axes of rocking of said levers to, the points of connection of said levers to said link means, whereby successive equal increments of movement of said worm wheel in either: sense from its normal position will effect progressively diminishing increments of movement of saidlevers and progressively more gradual movement of said anchor plate and spring load variation. 6. In a typewriter or like machine, a tram having a cross bar; instrumentalities to be operated; means for operating said instrumentalities including a plurality of mechanisms each comprising a finger-operable key member, said mechanisms including a set of corresponding elements deployed along, adjacent, and in spaced relation to said cross bar; an elongated spring anchor plate formed with two elongated slots the longer dimensions of which are transverse to the longer dimension of said plate; two guide studs fast with choredto said anchor plate and being connected respectively to said elements for urging said key members to normal, inactive positions; two levers mounted to rock on said guide studs respectively and being operatively connected to said anchor plate; link means connecting said levers to rock i conlointly for moving said anchor plate relatively j to said set of corresponding elements to thereby vary the loading of said springs; a worm wheel; means connecting said worm wheel to said link ,means for operating the latter in response to turning of said worm wheel; and a manually operable worm for operating said worm wheel.

7. In a typewriter or like machine, a frame having a cross bar; instrumentalities to be operated; means for operating said instrumentalities including a plurality of mechanisms each comprising a finger-operable key member, said mechanisms including a set of corresponding elements deployed along, adjacent, and in spaced relation to said cross bar; an elongated spring anchor plate formed with two elongated slots the longer dimensions of which are transverse to the longer dimension of said plate; two parallel guide studs fast with said cross bar and extending through said slots for guiding said plate for movements towards and from said set of corresponding elements; a plurality of pre-loaded normalizing springs anchored to said anchor plate and being connected respectively to said elements for urging said key members to normal, inactive positions; two levers mounted to rock on said guide studs respectively and being operatively connected to said anchor plate; link means connecting said levers to rock conjointly for moving said anchor plate relatively to said set of corresponding elements to thereby vary the loading of said springs; a worm wheel mounted to turn about an axis parallel to said studs; means connecting said worm wheel to said link means for operating .the latter in response to turning of said worm wheel; and a manually operable worm for operating said worm wheel, said worm wheel, said levers, and said link means being adapted to occupy normal positions corresponding to an average desired spring loading and being movable in opposite senses from said normal positions for increasing or decreasing said spring loadingsaid worm wheel, said levers, and said link means being so relatively proportioned and positioned that when they are in said normal positions a line extending from the axis of rotation of said worm wheel to the point of connection of said worm,

wheel to said link means is perpendicular to said link means and is parallel to lines extending respectively from the axes of rocking of said levers to the points of connection of said levers to said link means, whereby successive equal increments of movement of said worm wheel in either sense from its normal position will effect progressively diminishing increments of movement of said levers and progressively more gradual movement of said anchor plate and spring load variation.

8. In a typewriter or like machine, a frame having a cross bar; instrumentalities to be operated; means for operating said instrumentalities including a plurality of mechanisms each comprising a finger-operable key member, said mechanisms including a set of corresponding elements deployed along, adjacent, and in spaced relation to said cross bar; an elongated spring anchor plate formed with two elongated slot the longer dimensions of which are transverse to the longer dimension of said plate; two guide studs fast with said cross bar and extending through said slots for guiding said plate for movements toward and from said set of corresponding elements; a plurality of pre-loaded normalizing springs anchored to said anchor plate and being connected respectively to said elements for urging said key members to normal, inactive positions; two levers mounted to rock on said guide studs respectively and being operatively connected to said anchor plate, said anchor plate being positioned between said levers and said cross bar, and said guide studs having heads abutting said levers for holding the latter against said anchor plate and for thereby holding said anchor plate against said cross bar; link means connecting said levers to rock conjointly for moving said anchor plate relatively to said set of correspondin elements to thereby vary the loading of said springs; and manually operable means for operating said link means to effect such rocking of said levers.

9. In a typewriter or like machine, a frame having a cross bar; instrumentalities to be operated; means for operating said instrumentalities including a plurality of mechanisms each comprising a finger-operable key member, said mechanisms including a set of corresponding elements deployed along, adjacent, and in spaced relation to said cross bar; an elongated spring anchor plate including a fiat body part and a ledge part extending out of the plane of the body part, said body part being formed with two elongated slots the longer dimensions of which are transverse to the longer dimension of said plate; two guide studs fast with said cross bar and extending through said slots for guiding said plate for movements towards and from said set of corresponding elements; a plurality of pre-loaded normalizing springs anchored to said anchor plate and being connected respectively to said ele ments for urging said key members to normal, inactive positions; two levers mounted to rock on said guide studs respectively and having arms engaging said ledge part for pressing thereupon in opposition to the force tending to shift said plate due to the loading of said springs; and means for rocking said levers conjointly for effecting shifting of said plate to thereby vary the loading of said springs.

10. In a ,typewriter or like machine, a frame having a cross bar; instrumentalities to be operated; means for operating said instrumentalities including a plurality of mechanisms each comprising a finger-operable key member, said mechanisms including a set of corresponding elements deployed along, adjacent, and in spaced relation to said cross bar; an elongated spring anchor plate including a flat body part and .a ledge part extending out of the plane of the body part, said body part being formed with two elongated slots the longer dimensions of which are transverse to the longer dimension of said plate; two guide studs fast with said cross bar and extending through said slots for guiding said plate for movements towards and from said set of corresponding elements; a plurality of pre-loaded normalizing springs interposed under compression between said anchor plate and said ele ments respectively for biasing said plate and said set of elements relatively apart and thereby urging said key members to normal inactive positions; two levers mounted to rock on said guide studs respectively and having arms engaging said ledge part for pressing thereupon in opposition to the force exerted by said springs; link means connecting said levers for conjoint rocking; and manually operable means for operating said link means to rock said levers and thereby to effect shifting of said plate and variation of the compressive loading of said springs.

11. In a typewriter or like machine, a frame; instrumentalities to be operated; means for operating said instrumentalities including a plurality of mechanisms each comprising a fingeroperable key member; a spring anchor plate; means mounting said plate on said frame for shifting movement towards and away from elements of said mechanisms; a plurality of preloaded normalizing sprlngs anchored to said anchor plate and being connected respectively to said mechanism elements for urging said key members to normal, inactive positions; two levers mounted in mutually spaced relation on said frame and having portions operatively connected to said anchor plate; and means for rocking said levers in unison to effect shifting of said plate on said frame to thereby vary the loading of said springs.

12. In a typewriter or like machine, a frame, instrumentalities to be operated; means for operating said instrumentalities including a plurality of mechanisms each comprising a fingeroperable key member; a spring anchor plate; means mounting said plate on said frame for shifting movement towards and away from elements of said mechanisms; a plurality of preloaded normalizing springs anchored to said anchor plate and being connected respectively to said mechanism elements for urging said key members to normal, inactive positions; two 1evers mounted in mutually spaced relation on said frame and having portions operatively connected to said anchor plate; means for rocking said levers in unison to effect shifting of said plate on said frame to thereby vary the loading of said springs; an indicator part on said frame; and an extension on one of said levers cooperable with said part for showing the adjustment of said anchor plate and the loading of said springs.

13. In a typewriter or like machine, a frame including a mechanism mounting portion at the rear of the frame and a keyboard enclosing portion at the front of the frame; a cross bar on said frame extending end-to-end thereof substantially at the junctions of said frame portions and above said keyboard enclosing portion; instrumentalities to be operated mounted on said mechanism mounting portion of said frame; means for operating said instrumentalities including a plurality of mechanisms mounted on said mechanism mounting portion of said frame and each comprising a finger-operable key member projecting into said keyboard enclosing portion of said frame; an elongated spring anchor plate mounted in face-to-face contact with the front of said cross bar and being formed with two spaced elongated slots the longer dimensions of which are vertical; two guide studs extending respectively through said slots from the front of the machine and having threaded connection with said cross bar; a plurality of preloaded normalizing springs anchored to said anchor plate and being connected to elements of said mechanisms disposed below said anchor plate for urging said key members to normal, inactive positions; two levers mounted in face-to-face contact with the front of said anchor plate and being rockable on said' guide studs; parts on said levers operatively connected to said anchor plate; heads on said guide studs engaging the front faces of said levers for holding them against said anchor plate and for holding the latter against said cross bar, said guide studs being removable for enabling said anchor plate and said levers to be detached as a subassembly from said frame by movement forwardly away from said cross bar; and means for rocking said levers in unison for effecting vertical shifting of said anchor plate to thereby vary the loading of said springs.

14. In a power operated typewriter or like machine, instrumentalities to be operated; a power driven member; means for effecting selective operation of said instrumentalities by said power driven member, each of said mechanisms comprising an actuator connected to one of said instrumentalities, a finger-operable key member, and an intermediate lever operable by the associated key member for effecting connection of the associated actuator with said power driven member and operation of the associated instrumentality, the intermediate levers of said mechanisms being arranged in line; a spring anchor plate; means mounting said anchor plate on said frame to extend parallel to the alignment of said intermediate levers and in spaced relation to said levers; a plurality of pre-loaded normalizing springs anchored to said anchor plate and being connected respectively to said intermediate lements for urging said key members to normal, inactive positions; two adjusting levers mounted in mutually spaced relation on said frame and being operatively connected to said anchor plate; and means for rocking said adjusting levers in unison to effect shifting of said plate on said frame to thereby vary the loading of said springs.

WILLIAM H. KUPPER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,021,153 Kurowski May 26, 1912 1,053,449 Steele -I Feb. 18, 1913 2,474,741 Kittel June 28, 1949 

